<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8" />
		<title>demo</title>
	</head>
	<body>
		<script type="text/javascript" >
			let obj = {
				a:1,
				b:2,
				c:a+b
			}

			console.log(obj)
		</script>
	</body>
</html>